Electronic device and housing

ABSTRACT

The invention provides an electronic device that is environment-friendly and capable of achieving satisfactory noise prevention effect at low cost, and a housing implementing such electronic device. The housing has an electronic circuit disposed therein, and includes a component exposure section in which part of a conductive component disposed in the housing is exposed outward, a plate section made of a conductive material having a predetermined thickness, and spreading at a distance from the component exposure section, and a bridge section with the overall thickness thereof larger than the thickness of the plate section, extending along the component exposure section and electrically connecting the plate section and the conductive component.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Divisional of application Ser. No. 11/080,640,filed on Mar. 16, 2005, the entire contents of which are incorporatedherein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electronic device having anelectronic circuit incorporated therein, and to a housing for the same.

2. Description of the Related Art

In recent years, as the number of kinds of accessible peripheral devicesis growing, note-type personal computers (hereinafter referred to as anote PC, for short) being a type of electronic device with built-inelectronic circuits have become more convenient. Accordingly, the kindand number of ports (connectors) used to connect to the peripheraldevices are being required to be increased. However, due to restrictedmounting space, it is difficult to mount many connectors of variouskinds all at once on a note PC itself. Thus, generally, each makeremploys a connection configuration such that a separate unit having manyconnectors of various kinds mounted thereon is provided, and that theseparate unit is detachably connected via a dedicated connector to thenote PC. In many cases, in view of the wiring on the printed board andof the usability of other units and the note PC, the dedicated connectoris mounted on the bottom face in the vicinity of the rear end of thenote PC. When the dedicated connector is mounted on such a location, thebottom face of the housing of the note PC must be bored to mount theconnector.

As a material for the bottom face side of the housing of the note PC,there is employed a metal plate-like member for the purposes, such asincreasing the strength of a housing and securing the escape path forstatic electricity. Thus, a boring for mounting the connector is to bepositioned around the end of the plate-like member. Also, at the rearend of the note PC, connectors, etc., are protruded outward from thehousing, and the shell (metal outer shell section) of the connector isinstalled in the vicinity of the boring of the plate-like member.

In a note PC having such a structure, it is known that, when staticelectricity is applied to the shell of connector by the user's bodycoming close to the shell or by other actions, due to the staticelectricity, there are generated noises which cause the electroniccircuit of the note PC to malfunction.

As a measure against such noises, there have been proposed a techniqueof plating the inner face of a plastic member constituting the outermostshell of a housing to thereby allow static electricity to escape to theplating film, and a technique of disposing a radiowave absorption sheetinside the housing to thereby prevent noises from entering theelectronic circuit (refer to Japanese Patent Laid-Open No. 2001-308574,for example).

The hitherto proposed techniques, however, can pose problems, such asincreasing the cost of note PCs, and hindering weight saving andreduction in thickness which are strongly requested of note PCs. Inaddition, in recent years, while reduction of adverse environmentaleffects as introduced when electronic devices are scrapped is stronglyrequested, the application of plating and radiowave absorption sheet canbring about significant adverse environmental effects.

These problems are posed not only by note PCs, but generally also byvarious electronic devices of which a noise countermeasure arerequested.

SUMMARY OF THE INVENTION

The present invention has been made in view of the above circumstancesand provides an electronic device that is environment-friendly andcapable of achieving satisfactory noise prevention effect at low cost,and a housing which can implement such electronic device.

An electronic device according to the invention includes an electroniccircuit; a housing having the electronic circuit disposed therein; and aconductive component disposed in the housing and having part thereofexposed outside the housing, wherein the housing includes a componentexposure section in which the conductive component is exposed outward, aplate section made of a conductive material having a predeterminedthickness and spreading at a distance from the component exposuresection, and a bridge section with the overall thickness thereof largerthan the thickness of the plate section, extending along the componentexposure section and electrically connecting the plate section and theconductive component.

Here, the bridge section may be composed of plural overlapping members,or alternatively may be a single member.

The electronic device according to the invention has a structure inwhich the overall thickness of the bridge section is larger than thethickness of the plate section. Thus, even when static electricity isapplied to a conductive component as typified by a connector component,the static electricity is allowed to rapidly escape through the bridgesection to the plate section, thereby suppressing the generation itselfof noises to achieve a large noise prevention effect. This structure isbased on a hitherto unknown detailed analysis regarding noise generationprinciple, which will be later described in detail. Due to thesimplicity and large effect implemented by the structure, the electronicdevices can be small and of low cost. In addition, while avoiding theuse of materials bringing about significant adverse environmentaleffects, such as plating and radiowave absorption sheet, the simplestructure of the electronic device according to the invention can beeasily realized with a metal plate or the like hardly causing adverseenvironmental effects.

The bridge section preferably includes a first section formed of theconductive material integrally with the plate section, and a secondsection overlapping and contacting the first section. In addition, thebridge section preferably includes a first section formed of theconductive material integrally with the plate section, and a secondsection overlapping and contacting the first section via a board spring.

The bridge section having the first and second sections of this type canbe easily formed. Also, the configuration in which the second sectioncontacts via a board spring the first section has high contactstability. Consequently, the noise prevention effect can be sufficientlymaintained even under severe environments, such as one with vibrationsapplied.

A housing according to the invention, having an electronic circuitdisposed therein, includes a component exposure section in which part ofa conductive component disposed in the housing is exposed outward, aplate section made of a conductive material having a predeterminedthickness, and spreading at a distance from the component exposuresection, and a bridge section with the overall thickness thereof largerthan the thickness of the plate section, extending along the componentexposure section and electrically connecting the plate section and theconductive component.

By employing the housing according to the invention, the above-describedelectronic device according to the invention can be implemented.

Regarding the housing of the invention, only its basic configurationwill be shown here so that repeated explanation thereof is omitted. Notonly the basic configuration but various configurations of the housingcorresponding to the above described respective configurations of theelectronic device are included in the scope of the invention.

As described above, according to the invention, the electronic devicebeing environment-friendly and capable of achieving satisfactory noiseprevention effect at low cost can be implemented.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing one embodiment of the invention;

FIG. 2 is a diagram showing a note PC connected to a separate unit;

FIG. 3 is a diagram showing the rear side of the note PC;

FIG. 4 is a first explanatory diagram to describe the internal structureof a main body side housing;

FIG. 5 is a second explanatory diagram to describe the internalstructure of the main body side housing;

FIG. 6 is a first explanatory diagram to describe the noise generationprinciple;

FIG. 7 is a second explanatory diagram to describe the noise generationprinciple;

FIG. 8 is a diagram showing a comparative example to which aconventional noise countermeasure is applied;

FIG. 9 is a first explanatory diagram to describe an operation of thenoise countermeasure according to the embodiment of the invention;

FIG. 10 is a second explanatory diagram to describe the operation of thenoise countermeasure according to the embodiment of the invention;

FIG. 11 is a diagram showing another embodiment of the invention; and

FIG. 12 is a diagram showing a metal member in which contactstabilization is achieved.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the invention will be described below with reference tothe drawings.

FIG. 1 is a diagram showing one embodiment of the invention.

In FIG. 1, a note-type personal computer (note PC) 10 corresponding toone embodiment of the invention is illustrated. The note PC 10 includesa main body 11 and an upper cover 12 that is openable and closablerelative to the main body 11. The upper cover 12 is constructed byincorporating a liquid crystal screen 14 into an upper cover sidehousing 13. The main body 11 is constructed by incorporating a pointingdevice 16 and keys of various kinds 17 into a main body side housing 15,and incorporating printed boards, semiconductor elements, storagedevices, etc. into the interior section of the main body side housing15. Also, as described later, various connectors are exposed outwardfrom the rear side of the main body side housing 15.

The note PC 10 is detachable relative to a separate unit 20, and isconnected via a dedicated connector 21 to the separate unit 20.

FIG. 2 is a diagram showing the note PC 10 connected to the separateunit 20.

The separate unit 20 is provided with many connectors of variousstandards for peripheral device so that various peripheral devices, suchas a display, a printer, an external storage device and a communicationunit, can be connected thereto. The note PC 10 can access theseperipheral devices of various kinds via the separate unit 20.

It is desired that the note PC 10 on its own can be connected to someperipheral devices. Thus, various connectors for peripheral device arealso provided on the rear side of the note PC 10.

FIG. 3 is a diagram showing the rear side of the note PC 10.

In the note PC 10, as the connectors for peripheral device, there areincorporated an output terminal 18 a of a first kind for externaldisplay, an output terminal 18 b of a second kind for external display,three USB connectors 18 c, 18 f and 18 g, a printer port 18 d, and anetwork connector 18 e, which are exposed outward from the rear side ofthe main body side housing 15. In addition, on the rear side of the mainbody side housing 15, there is also provided a power source inputterminal 19 which supplies the electrical power to the note PC 10.

Of various connectors shown here, two kinds of output terminals 18 a and18 b and a printer port 18 d for external display are exposed outwardfrom the main body side housing 15; the outer shell section (shell) ofthese connectors is made of metal. The connector with such shellcorresponds to one example of the conductive component according to theinvention; the rear side of the main body side housing 15 corresponds toone example of the component exposure section according to theinvention.

The internal structure of the main body side housing 15 will now bedescribed.

FIGS. 4 and 5 are explanatory diagrams to describe the internalstructure of the main body side housing 15.

On the bottom face side of the interior section of the main body sidehousing 15, there is incorporated a plate-like member 101 formed byprocessing a metal plate. The plate-like member 101 has a boring 101 aso that a connector 21 penetrates. Due to the presence of this boring101 a, the plate-like member 101 includes a large and wide plate section101 b and a slim bottleneck section 101 c. In addition, as shown in FIG.5, on the bottleneck section 101 c, there is overlapped and fastened aslim metal member 102 used for noise countermeasure. The plate section101 b of the plate-like member 101 corresponds to one example of theplate section according to the invention; the bottleneck section 101 cand metal member 102 corresponds to one example of the first and secondsections of the bridge section according to the invention, respectively.

According to the embodiment, as a method for fastening the bottlenecksection 101 c to the metal member 102, fastening with caulking isemployed. According to the invention, however, fastening with screw,etc. can also be alternatively employed. Furthermore, according to theinvention, the bottleneck section 101 c and the metal member 102 may beelectrically integrated by joining them with an adhesive, two-sidedtape, conductive tape or the like, instead of with fastening, oralternatively may be physically and electrically integrated withwelding.

The metal shells of the connectors shown in FIG. 3 are electricallyconnected to both the bottleneck section 101 c and the metal member 102.

Hereinafter, an operation of the noise countermeasure according to theembodiment will be described. Before the description of the operation,firstly a detailed analysis on the noise generation principle and acomparative example to which a conventional noise countermeasure isapplied will be described, and then the operation of the noisecountermeasure according to the embodiment will be described.

FIGS. 6 and 7 are explanatory diagrams to describe the noise generationprinciple. These diagrams are not intended to illustrate the abovedescribed embodiment. However, the same reference numerals are appliedto elements corresponding to FIGS. 4 and 5, and an explanation thereofis omitted.

In FIGS. 6 and 7, there is shown a case where a note PC having no noisecountermeasure applied thereto is placed on a steel desk 40. Inaddition, a connector shell 18 electrically connected to a bottlenecksection 101 c of a plate-like member 101, and a semiconductor element103 and printed board 104 each provided in the interior section of thenote PC are also shown. The connector is mounted on the printed board104.

When a finger 30, etc. of the user comes close to the connector shell18, static electricity accumulated in the user's body can be dischargedand applied to the connector shell 18. The static electricity is apt toflow through the bottleneck section 101 c to the plate section 101 b.However, the presence of a boring 101 a makes the impedance of thebottleneck section 101 c large, thus interrupting the flow of theelectrical current.

According to an analysis by the inventors, etc, it is evident that, atthis time, two kinds of noises, i.e. conduction noise traveling throughconductive material and radiation noise radiated into the air aregenerated. As described below, it is clear that, of the two kinds ofnoises, the malfunction of the semiconductor element 103 is caused bythe radiation noise.

Specifically, when static electricity is discharged from the user'sfinger 30, conduction noise and radiation noise are simultaneouslygenerated. When the energy of conduction noise is compared with that ofradiation noise, the energy of the radiation noise is larger than thatof the conduction noise because the impedance of the bottleneck section101 c is large. Then, the radiation noise travels through a spacebetween the steel desk 40 and plate-like member 101 while beingrepeatedly reflected, and proceeds through the opening section, gaps,etc. of the plate-like member 101 into the interior section of the notePC. After entering the interior section of the note PC, with a metalpattern 104 a provided as the signal pattern and power source pattern onthe printed board 104 functioning as an antenna, the radiation noisetravels to the semiconductor element 103, thus causing the malfunctionof the semiconductor element 103.

The noise generation principle like this has hitherto been unknown.Consequently, as a noise countermeasure, an idea that an electroniccircuit be covered with a conductive shield has prevailed.

A comparative example to which a noise countermeasure based on suchconventional idea is applied will now be described.

FIG. 8 is a diagram showing a comparative example to which theconventional noise countermeasure is applied. Also in FIG. 8, the samereference numerals are applied to elements corresponding to each of thedrawings used in the above descriptions, and an explanation thereof isomitted.

In the comparative example shown in FIG. 8, in addition to theplate-like member 101, a housing outer shell 105 made of plastic isprovided; the inner face of the housing outer shell 105 is plated; Theplating film of the housing outer shell 105 electrically contacts theconnector shell 18. Accordingly, static electricity applied to the shell18 also travels through the plating film of the housing outer shell 105.Consequently, an effect of reducing radiation noise is achieved.

However, in the comparative example like this, a large plating filmspreading over the inner surface of the housing outer shell 105 isneeded, thus hindering downsizing of the note PC and at the same timeincreasing the cost. Also, the presence of such plating film bringsabout adverse environmental effects when the note PC is scrapped.Accordingly, it is expected that the application of the structuredescribed in the comparative example into a note PC will soon becomeimpossible.

In addition to the comparative example shown in FIG. 8, there is also anidea that adequate radiowave absorption sheet is spread between thehousing outer shell 105 and plate-like member 101 to prevent all noisescoming from the outside from entering the plate-like member 101.However, similarly to the above described comparative example, thepresence of such radiowave absorption sheet also hinders downsizing andcost reduction of the note PC, and brings about adverse environmentaleffects.

Based on the above described noise generation principle and comparativeexample, an operation of the noise countermeasure according to theembodiment will be described.

FIGS. 9 and 10 are explanatory diagrams to describe an operation of thenoise countermeasure according to the embodiment. In FIGS. 9 and 10, thesame reference numerals are applied to elements corresponding to FIGS. 6to 8.

According to the embodiment, on the bottleneck section 101 c of theplate-like member 101, there is overlapped and fastened a slim metalmember 102. Also, the connector shell 18 is electrically connected toboth the bottleneck section 101 c and metal member 102. The overallthickness obtained by combining the bottleneck section 101 c and metalmember 102 is larger than the thickness of the plate section 101 b ofthe plate-like member 101; the overall impedance obtained by combiningthe bottleneck section 101 c and metal member 102 is small. Thus, evenwhen the user's finger 30 or the like comes close to the shell 18 todischarge static electricity, the electricity flows via each of thebottleneck section 101 c and metal member 102 to the plate section 101b, thereby suppressing the noise discharged. Consequently, regarding theprinted board 104 and semiconductor element 103 each incorporated in thenote PC, the malfunction caused by the metal pattern 104 a receiving thedischarged noise can be substantially prevented. By fabricating the notePC having the structure according to the embodiment to perform a staticelectricity evaluation, it can be determined that static electricityresistant strength is improved by several kV relative to theconventional art, thus satisfying the level required by the strictinternational standards.

Also, according to the embodiment, the noise countermeasure is achievedwith a very simple structure having the metal member 102 provided on thebottleneck section 101 c, thereby facilitating downsizing of the notePC, and also contributing to cost reduction. In addition, similarly tothe plate-like member 101, environment-friendly materials can be usedfor the metal member 102, which can easily reduce the impact of the notePC on environment.

Another embodiment of the invention will now be described.

FIG. 11 is a diagram showing another embodiment of the invention.

The another embodiment is substantially similar to the above describedembodiment except that the metal member for noise countermeasure isdisposed in a different location. Accordingly, the difference from theabove described embodiment will be mainly described here, and repeatedexplanation thereof is omitted.

According to the another embodiment, a slim metal member 107 is fastenedalong a bottleneck section 101 c to the lower side of the bottlenecksection 101 c, and the note PC is covered with a housing outer shell 106made of plastic which prevents the metal member 107, etc. from beingexposed.

The metal member 107 overlaps the bottleneck section 101 c. The metalmember 107 and bottleneck section 101 c constitute another example ofthe bridge section according to the invention. Also in this embodiment,the overall impedance of the metal member 107 and bottleneck section 101c is small, whereby static electricity escapes rapidly through the metalmember 107 and bottleneck section 101 c, thus reducing radiation noise.

In this way, the radiation noise reduction effect is large irrespectiveof where the metal member is disposed relative to the bottleneck section101 c. However, when the metal member is loosely fastened to thebottleneck section to thereby make the contact unstable, the reductioneffect is also made unstable. Therefore, it is desired that the contactbetween the bottleneck section and metal member is made stable.

FIG. 12 is a diagram showing a metal member in which contactstabilization is achieved.

The metal member 108 shown in FIG. 12, which is used instead of themetal member 102 shown in FIGS. 5, 9, and 10, or the metal member 107shown in FIG. 11, has a structure formed by providing a board springsection 108 b at both ends of a main body 108 a. The board springsection 108 b like this is formed by bending at both ends a metal boardout of which the metal member 108 is made, and then forming notches todivide the metal board into plural sections. The metal member 108 havingsuch structure strongly contacts the bottleneck section with the forceof the board spring section 108 b, and at the same time has largecontact stability. Accordingly, the radiation noise reduction effect asdescribed above can be stably utilized for long periods even undersevere environments, such as one with vibrations applied.

In the above descriptions, as one example of the bridge sectionaccording to the invention, there is shown one formed by disposing theslim metal member on the bottleneck section of the plate-like member.The bridge section according to the invention, however, may be onefabricated with a thicker material than the plate section separatelyfrom the plate section and attached to the plate section, oralternatively may be one obtained by processing a metal board in whichthe vicinity of the bridge section is originally thicker than the othersections of the metal board so that the bridge section is formedintegrally with the plate section.

Also, in the above descriptions, as one example of the electronic deviceaccording to the invention, the note PC is shown. The electronic deviceaccording to the invention, however, may be a computer other thannote-type one, or alternatively may be an electronic device other than acomputer, such as an electronic measurement device.

1. An electronic device comprising: an electronic circuit; a housinghaving the electronic circuit disposed therein; and a peripheral deviceconnector disposed in the housing and partially exposed outside thehousing, the housing including: an exposure section in which theperipheral device connector is exposed outward; a first conductivesection that is made of a conductive plate having a predeterminedthickness; and a second conductive section that electrically connectsthe first conductive section to the peripheral device connector, and hasan overall thickness larger than the thickness of the first conductivesection, wherein the first conductive section has an area larger thanthe second conductive section, and wherein the second conductive sectionhas the form of a plate.
 2. The electronic device according to claim 1,wherein the second conductive section comprises: a first portion that isformed of a conductive material integrally with the first conductivesection; and a second portion that contacts and overlaps the firstportion.
 3. The electronic device according to claim 1, wherein thesecond conductive section comprises: a first portion that is formed of aconductive material integrally with the first conductive section; and asecond portion that includes a spring in contact with the first portion.4. A housing having an electronic circuit disposed therein, comprising:an exposure section in which a peripheral device connector disposed inthe housing is exposed outward; a first conductive section that is madeof a conductive plate having a predetermined thickness and extends fromthe exposure section; and a second conductive section that electricallyconnects the first conductive section to the peripheral deviceconnector, and has an overall thickness larger than the thickness of thefirst conductive section, wherein the first conductive section has anarea larger than the second conductive section, and wherein the secondconductive section has the form of a plate.
 5. The housing according toclaim 4, wherein the second conductive section comprises: a firstportion that is formed of a conductive material integrally with thefirst conductive section; and a second portion that contacts andoverlaps the first portion.
 6. The housing according to claim 4, whereinthe second conductive section comprises: a first portion that is formedof a conductive material integrally with the first conductive section;and a second portion that includes a spring in contact with the firstportion.